OS/2 1.x 1.0

OS/2 was originally a joint effort between IBM and Microsoft. It grew out of efforts to create a Multitasking MS-DOS. It was intended to be the future OS for IBM's new PS/2 series. At release it competed against Microsoft's Windows GUI shell, but most users continued to use DOS. OS/2 1.x was used as the basis for Citrix Multiuser

1.x was heavily criticized for its poor backwards compatibility, heavier system requirements, design decisions made in order to support 286s instead of just 386s, poor hardware compatiblity, and lack of third party driver support. There was an inaccurate, but justifiable, common belief that OS/2 could only run on genuine IBM hardware.

Still, it was believed that all future software development would be for OS/2, until an almost overnight fallout between IBM and Microsoft shifted the spotlight to the yet to be developed Windows NT.